For the purposes of this study, and in preliminary experimentation, we found that Constraints () are the most effective as implemented within the Lazy method. This is not surprising, since relaxing this constraint set leads to an MIP that is equivalent to an assignment or bi-partite matching problem [1]}. These problems are known to be pseudo-polynomial, and can hence be solved efficiently. Note, there is a potential disadvantage to this approach, which is that the link between the \(x\)  and \(y\) /\(z\)  variables are broken, which can mean that for specific problem instances, an initial feasible solution can be hard to find (i.e. too many lazy constraints are needed to find a feasible solution).
